This disclosure relates to the field of wireless telecommunications and more particularly to a sleeve enclosure for receiving a wireless communicating device and for boosting the signal of the device. Cellular telephones are notorious for dropping calls, for poor or intermittent transmission and reception of signal and for lack of consistent signal strength. Solutions to this problem include providing more and more-closely spaced base stations, the use of add-on antennas and the use of complimentary antennas. For instance, publication WO 2020/098540 discloses a double molding process wherein in a first molding step, an antenna is embedded within a resin jacket and in a second molding step the resin jacket is embedded within a device case by an insertion molding processes. Likewise, publication JP2006/148751 discloses the coupling of antennas built into a cover which when placed over the case of a portable terminal are positioned in close proximity to internal antennas of the terminal and are thereby able to be inductively coupled for strengthening transmitted signals. However, the prior art fails to describe a high efficiency proximity probe which is embedded within and located in a phone sleeve in a position for coupling with the phone's internal antenna and which is electrically connected with an external antenna via conductive paths also embedded within the phone sleeve. The presently described apparatus overcomes the drawbacks and failings of the prior art.